1. Field of the Invention
The invention relates generally to catalysts and catalytic processes for reforming oxygen-containing hydrocarbons and, more specifically, the invention relates to a method of converting oxygen-containing hydrocarbons to useful products using catalysts derived from hydrotalcite-like catalyst precursors.
2. Description of Related Technology
The use of metal-containing catalysts in converting oxygen-containing hydrocarbons to useful products (e.g. methanol reforming the conversion of methanol to carbon dioxide and hydrogen by reaction of methanol and water) is well known. Conventionally, the oxygen-containing hydrocarbon is reacted with excess steam over a catalyst, generally in the form of mixed metal oxides, such as CuO/ZnO/Al.sub.2 O.sub.3, to produce useful products (e.g., carbon dioxide and hydrogen). The catalysts and processes used for steam reforming of oxygen-containing hydrocarbons, however, have suffered from various disadvantages.
Mixed metal oxide catalysts are readily susceptible to deactivation and, furthermore, the active sites present in mixed metal oxide catalysts tend to deactivate at differing rates, which adversely affects selectivity as well as activity.
Typical methanol reforming (and other) processes of the prior art require excess steam to increase the degree of conversion of the process, which adds greatly to the energy costs of the process. Some prior hydrocarbon conversion catalysts are difficult to prepare and/or exhibit low activity and/or selectivity. Some prior processes require that the hydrocarbon and/or water reactants be supplied to the reactor in gaseous form, which further increases the cost of the process. Further, steam, heat, and time are major factors leading to deactivation of conventional mixed metal oxides due to sintering, which results in the loss of surface area and formation of aggregates.